A German man who poisoned several coworkers for years, sprinkling toxic metals into their food and drinks, arrested last year, was sentenced to life in prison on Thursday.

His lawyers are planning to appeal. He, now 57 old, identified only as Klaus O. in line with German privacy rules, was an employee four decades of the metal fittings company in Schloss Holte-Stukenbrock and was known rarely communicating because he had no friends. The evidence of his criminal activity was proved by installing a hidden camera in the break room. He was found dusting food of his colleagues' bags with a white powder later discovered as highly toxic. His colleagues ingested chemicals and began to fall victim to various illnesses.

The convicted man

In a search of his home police discovered a makeshift laboratory where they found a number of heavy metals, including lead acetate, cadmium, lead and mercury. Judge Georg Zimmermann described this chemical arsenal as "more dangerous than all combat agents used in World War II." Two of his colleagues suffered serious kidney damage. A third has brain damage and is currently in a vegetative state, unlikely to recover. A psychiatrist had confirmed that the defendant was not only fully responsible for his actions, but that he might strike again, if given a chance.The convicted man is suspected for a string of 21 deaths of former employees at the same company. Nobody has any idea about the motivation of this man. The actual verdict did not mark the end of the investigation.